Production of sheets and other shapes from molten metal



March 23, 1937. T. SENDZIMIR PRODUCTION OF SHEETS AND OTHER SHAPES FROM MOLTEN METAL Filed July 15, 1955 3 Sheets-Sheet 1 INVENTOR $4050.52 Sf/VDZ/M/R. BY M alk v ATTORNEYS.

March 23, 1937; SENDZ|M|R 2,074,812

PRODUCTION OF SHEETS AND OTHER SHAPES FROM MOLTEN METAL Filed July 15, 1935 3 Sheets-Sheet 2 I NVEN TOR Dan/s2 SE/VDLZ/M/R QZZw/Y W n Q N ATTORNEYS March 23, 1937. r. SENDZIMIR 2,074,812

PRODUCTION OF SHEETS AND OTHER SHAPES FROM MOLTEN METAL Filed July 15, 1935 3 Sheets-Sheet 3 INVENTOR 720E052 SE/VDZ/M/B.

BY QQQMQMLN ATTORNEYS.

Patented Mar. 23, 1937 UNITED STATES PRODUCTION OF SHEETS AND OTHER SHAPES FROM Tadeusz Sendzimir, Katowice, Poland,

to The American Rolling Mi dletown,

Application July 15,

MOLTEN METAL assignor ll Company, Mid- Ohio, a corporation of Ohio 1935, Serial No. 31,358

In Poland October 16, 1932 8 Claims.

My invention relates to means and a process for eliminating a number of the steps now found necessary in the production of metal sheets and other shapes, and in particular in the production of sheets and shapes of iron and steel. In the well known practice, the iron or steel after being refined, as in an open hearth furnace, or otherwise, is cast into ingots. The ingots are subsequently heated in the soaking pits, and are then passed through a blooming mill to be rolled into billets, slabs, sheet bars, or other pieces suitable for subsequent processing. It is quite clear that these operations entail a great expense in equipment, labor and fuel, which could be saved if the steps were rendered unnecessary. However, a

casting of the ingots is a step which gives rise to certain peculiar difliculties, which it is an especial object of my invention to avoid. The cooling of the metal in the ingot mould results not only in a segregation of impurities or inclusions in certain parts of the metal, but also in the formation of hollow places, which, if large, are called pipes. These defects in the cast article result in the necessity of cutting off unusable portions thereof, or in "chipping or otherwise dressing the ingot before itmay be used and also, in the production of sheets or other shapes from the ingot, these defects cause defects in the finished article which are a primary source of rejection. In the casting of an ingot the initial chilling of the metal against the ingot mould walls results usually in the formation of a skin of crystals of relatively high purity, and the segregation of impurities toward the interior of the cast ingot. It will be clear that if a skin of metal as chilled could be withdrawn and used as such, not only would such a skin be free of substantial inclusions or gas pockets, but also the metal would be obtained in a form requiring less reduction to fit it for its ultimate use. It is an object of my invention to accomplish this.

Moreover, in the casting of ingots difiiculty is sometimes had by reason of the spattering of the metal as it is initially introduced into the mould, and it will be obvious that if the chilling of a skin of metal could be carried on in a substan-' tially continuous and even manner, these diiilculties could likewise be avoided. It is an object of my invention to accomplish this.

It is a further object of my invention to produce shapes of semi-finished form direct from molten metal, and where the shapes are intended for ultimate mechanical working, such as rolling, to finish these shapes where desired, in forms which are particularly adapted to the mechanical working process contemplated.

It is a further object of my invention to produce desired shapes without encountering the disadvantageous effects of oxidation as the shapes are 60 being formed. These and other objects of my inventlon which will be set forth hereinafter, or will be apparent to one'skilled in the art upon reading these specifications, I accomplish by that certain construction and arrangement of parts and in that process of which I shall now describe an exemplary embodiment, reference being had to the drawings which accompany this specification, and in which:

Figure 1 is a semi-diagrammatic elevational view, with parts in section showing an operative embodiment of my invention.

Figs. 2 and 3 are respectively vertical and horizontal sections through one form of cooling drum which I may employ.

Fig. 3a shows a sectional shape of the metal article produced by the devices of Figs. 2 and 3.

Fig. 4 is a plan view of a roll having heating means.

Fig. 5 is a sectional view of a roll adapted to produce a particular shape in the metal article.

Fig. 5a shows the sectional-shape of the article produced by the roll of Fig. 5.

Figs. 6 and 7 are respectively a vertical section and a plan view with a part in section, of another type of roll.

Fig. 8 shows a modification of my invention where a composite strip is being cast, the figure showing a cross section similar to that of Fig. 1.

Fig. 9 is a cross sectionalview of another modification of my invention showing the building up of a previously formed strip.

Briefly, in the practice of my invention, I provide a body of molten metal, and at the place where the molten metal is to be operated upon I preferably provide means for skimming the slag from it, and also preferably I provide means for maintaining in contact therewith an inert or a non-oxidizing atmosphere. In the formation of my shapes, I cool a portion of the metal in contact with the body thereof locally, so as to solidify it sufficiently to hold its shape, and then I withdraw the cooled metal, preferably continuously, while cooling more metal. It is possible to do this by cooling the surface of a bath of metal by means acting to absorb the radiated heat very rapidly, and to withdraw the cooled metal from the bath without bringing it into direct contact with the cooling means. This operation would imply the location of heat absorbing means adjacent an exposed surface of the molten metal, and means for withdrawing the metal as it solidifies. I prefer to contact the surface of the metal with a cooling means however, not only because this is more efllcient, but also because by the use of a contacting cooling means the dimensions and configuration of the metal shape being made may be more accurately and easily controlled.

To illustrate a simple exemplary form of my invention, reference is made to Fig. 1, where a container I is provided for the molten metal. Under some circumstances, this container may be a part of a refining furnace, and in other instances it may be a separate container, with -.-5 heating means, if necessary, to maintain the bath molten. A dividing partition 2 dips into the molten metal and serves to skim the slag therefrom, the metal passing under this partition and into a localized space marked la, where it is to 1 be treated as I shall next describe. Preferably a removable housing indicated at I is placed over the space in which the metal is to be treated, and serves in part as a gas seal so that the atmosphere which contacts the molten metal may be controlled by known means to prevent oxidation or to secure other effects.

Within the housing 3, and dipping into the molten metal I, I have shown a cooling drum 5 mounted upon a shaft 6. The shaft extends through the side of the treatment chamber, and is provided with a gear wheel I, driven by a worm I on a shaft 9, to which power may be applied for rotating the drum 5. Appropriate means are provided for cooling the drum 5, such as means for admitting a cooling fluid, steam, or the like, into the interior thereof. It will be understood that the drum 5, where it contacts the molten metal, rapidly abstracts heat therefrom so that a skin of solidified metal is formed thereon. This skin may be continuously stripped from the surface of the drum 5, as by being removed over' a roll it and carried through a hole in the housing. If an inert atmosphere is to be maintained in the housing, preferably there will be some sealing means for this hole, such as sealing rolls indicated atically at H. I have next shown the strip i2 pasing through a leveling mill l3, which may be of the two high type, and afterward through one or more rolling mills u and I8, which may be of the four-high type adapted to produce heavy reductions in the metal.

Afterward, the rolled strip may be passed r through an annealing space indicated diagrammatically at it, where it may be annealed either by the persistence of its own heat, or by heat artiflcially applied. The heat treatment of the piece may be carried on under neutral or reducing conditions if this is desired, the annealing space being gas sealed, and the atmosphere therein controlled. It may then be passed through a cooling space indicated diagrammatically at H; and in finished form it may be sheared to sheet length or coiled into a coil i8.- The thickness of the sheet thus produced may be controlled by several factors, including the cooling effect of the drum 5 and the rapidity of rotation thereof. The metal, if the drum has a low cooling rate, will solidify upon the surface thereof in a very pure state, and in a form characterized by needle-like crystals directed at right angles to the heat absorbing surface. It will be substantially free of inclusions, and will also be uniform in character. On the other hand, if the drum has a high cooling rate the metal will solidify in very small crystals of approximately the same analysis of the melt, the gases and non-metallic inclusions being entrapped, but without segregations.

In the practice of my invention, where shapes of sheet-like character are desired, I prefer to make my drum 5 with a cylindrical body is as shown in Figs. 2 and 3 of metal or other substance which readily conducts heat. The cooling may be "5 carried on in any one of a number of ways. One

way is by providing a coil of pipe 20, within the cylinder l9, and having inlets and outlets 2| and 12 extending through the trunnions 23 of the cylinder. The coil of pipe may be a part of or included within a cylinder of metal indicated at 24 somewhat interspaced, as shown, from the cylindrical shell i9, and adapted to cool the shell by absorbing heat convected therefrom. In order to gauge the side edges of the strip being produced, I prefer to provide my cylinder with end flange portions 25. These may be made, if desired, of substance which conducts heat but poorly, so that upon immersion in the bath of molten metal these flanges approach the liquid temperature thereof. When this is done, solidification of metal on the flanges is prevented, and a sheet of metal of substantially constant width solidifies only upon the cylindrical portion ii. The whole structure of Figs. 2 and 3 may be rotated, or the shell I! mayvbe caused to rotate. with or without the flanges, while other parts of the apparatus remain stationary.

In the structure of these figures, I have shown means for cooling the surface ofthe cylindrical shell length; and the resultant 'strip produced is shown at 28 in Fig. 3a as being of substantially uniform cross section.

Where a solidifled metal shape of very high purity is desired, it may be secured by controlling the temperature of the cylindrical shell ll to a point such that the solidification of the metal occurs more slowly. Again the thickness of the shape produced may be controlled by the speed at which the drum turns in the molten metal. For temperature control, it is competent to include within the shell I, electrical heating means indicated at 21 in Fig. 4. Also where heat resistant materials are available, it is competent to make the flanges 20 (in Fig. 4) thin and of heat conducting material, so that their edges may approach the heat of the bath.

In Fig. 5, I have shown a cylinder having the shell I! and flanges 2!, but equipped with a cooling means 2!, which, as shown, is adapted to cool the surface of the cylindrical shell unequally. In the particular embodiment illustrated, the cooling means acts to coolthe ends of the shell more than the central portion thereof. so that more metal solidifies near the ends of the cylinder than elsewhere, thus giving a cross sectional shape to the strip produced which is illustrated at II in Fig. So as being thicker at the ends than in the middle. Where a crowned rolling piece is desired, it will be competent, of course, to cool the cylinder shell I! in such a .way as to give the resultant piece which is thicker in the center than at its edges.

Interior cooling of the cylindrical shell is, of course, not necessary in all instances. I have shown in Figs. 6 and '1, the shell I! as being continuously cooled in that portion thereof which is not dipping into the bath by; external cooling means 3i. These means, if desired, may contact the surface of the cylindrical shell I, and have a wiping or cleaning action thereon; in the particular form in which I have illustrated them they constitute a cooled jacket out of contact with the surface of the cylinder, but absorbing rapidly the heat radiated from the surface thereof.

It will be understood that the level of the molten metal in the container may be maintained by additions from time to time, or otherwise. I have already indicated that the surface of the molten metal and the surface of the formed shape may be protected by inert gases. It is also possible to I! substantially evenly throughout its protect the surface of the molten metal by the use of coverings such as fused salts, slags and the like, where these can be controlled. It will be obvious that the surface of the heat absorbingbody can have various shapes, as well as various rates of cooling in its several parts, and that in this way various shapes may be produced. Two or more of the heat absorbing bodies may be arranged in a condition as shown lnFig. 8, and the resulting strips or other shapes can be removed separately or together. It is thus possible to provide two of the drums 5 rotating in opposite directions and close to each other, so that a composite strip is produced as at 40, the thickness of which is quite accurately gauged by the distance of the surfaces of the drums from each other where they approach closest. In the event that two parallel moving metal strips are pulled out simultaneously and processed as a single strip, the two strips may weld together as formed, i. e. during the first contact as at 40, or afterward, during further processing, such as the rolling indicated at H. A single strip can also b passed through the molten metal with another heat absorbing body such as thedrum which I have described. This is illustrated in Fig. 9. In this way, stripsor other shapes may be produced which are not homogeneous as to metallic content, but combine two or more layers or plies of metals or alloys of different compositions. When combining two or more strips, it is possible to change the crystal direction, ordinarily normal to the surface of the strips, by slight differentials in the speeds of the several strips.

Modifications may be made in my invention without departing from the spirit thereof.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent, is:-

1. A process of producing shapes directly from molten metal, which comprises providing a body of molten metal in a furnace, segregating a portion of said metal for casting purposes while maintaining it in heat exchange relationship with the metal in the furnace, contacting the surface of said segregated portion with a heat absorbing body so as to chill and solidify a relatively thin portion of said molten metal on the surface of said heat absorbing body, and removing the solidifled portion thereof on the body of said cooling means, while protecting said segregated portion of said molten metal and said solidified metal from chemical action.

2. A process of producing shapes from molten metal, which comprises providing a body of molten metal in a furnace, segregating a portion of said metal for casting purposes while maintaining it in heat exchange relationship with the metal in the furnace, bringing into contact with said segregated portion a cooled surface so as to solidify a relatively thin portion of said metal, while protecting said segregated portion of said molten metal from chemical action and controlling the cooling eflect of said surface diflerently 0 in different parts, so as to vary the cross-sectional thickness of the metal solidified thereon in various parts thereof.

3. In combination, furnace means for maintaining a bath of metal molten, means for segregating a portion of said molten metal for casting piu'poses while maintaining it in heat exchange relationship with the metal in the furnace, a cylinder located to dip into said egregated portion of said molten metal, means for cooling said cylinder, means for moving and for stripping from the surface of said cylinder a skin of metal solidified thereon, and means for maintaining said molten metal and said solidified metal under inert chemical conditions.

4. In combination, furnace means for maintaining a bath of metal molten, means for segregating a portion of said molten metal for castingpurposes while maintaining it in heat exchange relationship with the metal in the furnace, means for cooling a portion of said segregated metal, means for controlling the shape of the solidified part of said cooled portion, means for continuously withdrawing said solidified part, and means for protecting said segregated metal and said solidified portion from chemical action.

5. In combination, furnace means for maintaining a bath of mega] molten, means for segregating a portion of said molten metal for casting purposes while maintaining it in heat exchange relationship with the metal in the furnace, a cylinder located to dip into said segregated portion of said molten metal, means for cooling said cylinder, means for moving and for stripping from the surface of said cylinder a skin of metal solidified thereon, and means for protecting said segregated metal and said solidified portion from chemical action.

6. In combination, furnace means for maintaining a bath of metal molten, means for segregating a portion of said molten metal for casting purposes while maintaining it in heat exchange relationship with the metal in the furnace, a

cylinder located to dip into said segregated portion of said molten metal, means for cooling said cylinder, and means for moving and for stripping from the surface of said cylinder a skin of metal solidified thereon, said segregating means comprising a dividing wall dipping into said molten metal, and serving to remove the slag therefrom, and means for protecting said segregated metal and said solidified portion from chemical action.

'7. A process of producing shapes directly from molten metal, which comprises providing a body of molten metal in a furnace, segregating a portion ofsaid metal for casting purposes while maintaining it in heat exchange relationship with the metal in the furnace, contacting the surface a of said segregated portion with a pair of adjacent, oppositely rotating heat absorbing bodies, determining the thickness of the portion of said molten metal solidified thereby by adjusting the distance between the said heat absorbing bodies,

to be built up through said segregated portion,

concurrently abstracting heat therefrom, so as to chill and solidify thereon a relatively thin portion of said molten metal while protecting said segregated portion of said molten metal and said solidified metal from chemical action.

TADEUSZ BENDZIM'IR. 

